晶格畸变分析及其在半导体量子点结构中的应用

在适当的成像条件下可以直接从高分辨透射电子像（HRTEM）以接近原子级的分辨率进行晶格畸变分析。本综述介绍晶格畸变分析（LADIA）程序包及其在半导体自组装量子点（QD）系统中的应用。对多层InP小QD系统中畸变分布的分析表明：光致发光（PL）能量峰位的红移和QD中的应变弛豫直接相关。在慢速生长的InAs大QD系统中应变引起的元素互溶是PL峰位蓝移的主要因素。多层系统中QD的垂直叠合可解释为间隔层厚度低于临界值时生长前沿的横向张应变的作用。研究了生长以后不同条件快速退火对QD稳定性的影响，观测到垂直叠合的InPQD中出现各向异性的退火不稳定性。

Lattice distortion analysis and its application to semiconductor quantum dot structures

Lattice distortion analysis may be carried out directly from high-resolution transmission electron microscopy(HRTEM) images under favourable experimental imaging conditions with near atomic resolution.This review introduces the program package LADIA for lattice distortion analysis and its application to semiconductor self-assembled quantum dot(QD) systems.In the case of small InP QDs the evaluation of strain distribution in multilayer QD structures leads to a direct correlation between the red shift of photoluminescence(PL) energy peak position and the strain reduction in the QDs.Strain induced material intermixing is found to be dominant effect to the blue shift of PL peak position in the case of slowly grown large InAs QDs.Vertical alignment of QDs in multilayers is interpreted with lateral tensile strain at the growth front,when the thickness of the spacer layer is below a critical value.Stability of QDs under various conditions of ex-situ postgrowth rapid annealing is studied,and an anisotropic thermal instability of vertically stacked InP QDs has been revealed.